[POWERPC] spufs: Fix libassist accounting

We're currently too permissive with counting libassist calls - fix the
check on the SPE stop-and-signal status.
Signed-off-by: NJeremy Kerr <jk@ozlabs.org>
Signed-off-by: NPaul Mackerras <paulus@samba.org>

arch/powerpc/platforms/cell/spufs/run.c

@@ -352,7 +352,7 @@ long spufs_run_spu(struct file *file, struct spu_context *ctx,
 				       SPU_STATUS_SINGLE_STEP)));
 
 	if ((status & SPU_STATUS_STOPPED_BY_STOP) &&
-	    ((status >> SPU_STOP_STATUS_SHIFT) & 0x2100))
+	    (((status >> SPU_STOP_STATUS_SHIFT) & 0x3f00) == 0x2100))
 		ctx->stats.libassist++;
 
 	ctx->ops->master_stop(ctx);